Summary: More than a quarter of the exoplanets studied by NASA could be ocean worlds, with a majority possibly harboring oceans beneath layers of surface ice.
Original author and publication date: NASA Goddard Space Flight Center – June 19, 2020
Futurizonte Editor’s Note: Perhaps we are not as unique as we (humans) think we are, after all. Perhaps we have many cousins we are yet to meet.
From the article:
Several years ago, planetary scientist Lynnae Quick began to wonder whether any of the more than 4,000 known exoplanets, or planets beyond our solar system, might resemble some of the watery moons around Jupiter and Saturn. Though some of these moons don’t have atmospheres and are covered in ice, they are still among the top targets in NASA’s search for life beyond Earth. Saturn’s moon Enceladus and Jupiter’s moon Europa, which scientists classify as “ocean worlds,” are good examples.
“Plumes of water erupt from Europa and Enceladus, so we can tell that these bodies have subsurface oceans beneath their ice shells, and they have energy that drives the plumes, which are two requirements for life as we know it,” says Quick, a NASA planetary scientist who specializes in volcanism and ocean worlds. “So if we’re thinking about these places as being possibly habitable, maybe bigger versions of them in other planetary systems are habitable too.”
Quick, of NASA’s Goddard Space Flight Center in Greenbelt, Maryland, decided to explore whether — hypothetically — there are planets similar to Europa and Enceladus in the Milky Way galaxy. And, could they, too, be geologically active enough to shoot plumes through their surfaces that could one day be detected by telescopes.
Through a mathematical analysis of several dozen exoplanets, including planets in the nearby TRAPPIST-1 system, Quick and her colleagues learned something significant: More than a quarter of the exoplanets they studied could be ocean worlds, with a majority possibly harboring oceans beneath layers of surface ice, similar to Europa and Enceladus. Additionally, many of these planets could be releasing more energy than Europa and Enceladus.
Scientists may one day be able to test Quick’s predictions by measuring the heat emitted from an exoplanet or by detecting volcanic or cryovolcanic (liquid or vapor instead of molten rock) eruptions in the wavelengths of light emitted by molecules in a planet’s atmosphere. For now, scientists cannot see many exoplanets in any detail. Alas, they are too far away and too drowned out by the light of their stars. But by considering the only information available — exoplanet sizes, masses and distances from their stars — scientists like Quick and her colleagues can tap mathematical models and our understanding of the solar system to try to imagine the conditions that could be shaping exoplanets into livable worlds or not.